(Wikimedia Commons)

Lucy (Australopithecus) was discovered by Donald Johanson in the 1970s in Ethiopia.

Forty years ago, one of the most significant discoveries in the study of human evolution was made in Ethiopia. It was the fossilized remains of a human ancestor more than 3 million years old. But you probably know her as Lucy.

That's because the paleoanthropologist who discovered her, Donald Johanson, played one particular Beatles song over and over the night she was found.

Johanson will be giving a lecture Thursday at the Tempe Center for the Arts looking back on this famous fossil.